1. Field of the Invention
The present invention relates to the preparation of hydrogenated silanes by redistribution, and, more especially, to the preparation of a silane containing at least one Si--H bond by reacting a less hydrogenated or non-hydrogenated silane with an alkyl or aryl hydrosilane in the presence of a catalyst.
2. Description of the Prior Art
It is known to this art to prepare silanes containing at least two Si--H bonds by disproportionation of two hydrosilane molecules containing alkyl or aryl groups, if appropriate. Thus, French Pat. Nos. 2,096,605, 2,118,725, 2,261,977, 2,290,447, and 2,290,448 describe such disproportionation reactions in the presence of various catalysts, wherein such disproportionation reactions can be represented as follows: EQU 2R.sub.n H.sub.m SiX.sub.4-(n+m) .revreaction.R.sub.n H.sub.m+1 SiX.sub.3-(n+m) +R.sub.n H.sub.m-1 SiX.sub.5-(n+m)
in which n denotes an integer equal to 0, 1 or 2; m denotes an integer equal to 1, 2 or 3 with n+m.ltoreq.3, and R denotes an alkyl or aryl group and X a halogen.
It is also known to prepare alkyl or aryl hydrosilanes by redistribution between a molecule of hydrosilane and a molecule of alkyl or aryl halosilane. The described catalysts for these redistribution reactions are notably those which are the subject of French Pat. Nos. 1,603,167, 2,290,447, 2,467,855, 2,290,448, 2,096,605 and 2,119,477, wherein such redistribution reactions can be represented as follows: EQU H.sub.m SiX.sub.4-m +R.sub.n SiX.sub.4-n .fwdarw.H.sub.m-1 SiX.sub.5-m +R.sub.n HSiX.sub.3-n
in which m denotes an integer equal to 1, 2, 3 or 4 and n denotes an integer equal to 1, 2 or 3 and R denotes an alkyl or aryl group and X a halogen.